1. Technical Field of the Invention:
This invention relates to a drawing device for use in a drafting machine and a drawing pencil used therewith, and more particularly to a drawing pencil adapted to thrust a lead continuously and sequentially and an actuator device thereof.
2. Description of the Prior Art
Drawing devices for use in drafting machines adapted to thrust a pencil lead automatically and sequentially are disclosed in, for example, Japanese patent Publication No. 57-36789, Japanese Utility Model Publication No. 57-5193, and West Germany patent Laid-Open Specification No. 32 29 480.0, etc.
Since these prior art drawing devices for use in drafting machines, are not provided with any special mechanism to expel or remove the residual lead, it is necessary to repeat normal lead thrusting operations several or several ten times to enable the residual lead to be pushed out by the next new lead. Therefore, the residual lead expelling operation per se is troublesome and takes a long time, Further, such a lead expelling operation is disadvantageous in that since the length of the lead once thrusted at the leading end of the drawing pencil cannot be adjusted the lead is liable to break.